Breech device for firearms



Aug. 22,` 1944.'

J, KOUCKY BREECH DEVICE FOR FIREARMS Filed March 8. 1941 Patented Aug. 22, i944 entre BREECH DEVICE FOR FIREARMS Josef Keucky, Prague, Bohemia; vested in the ien Property Custodian Application March 8, 1941, Serial No.' 382,429 In Bohemia and Moravia December 22, 1939v 4 Claims.

The present invention relates to a breech device for iirearms especially for those of smaller caliber, whether it be a repeater, an automatic or semi-automatic rearm. The present invention relates to a breech device for such firearms in which projectiles of a, greater force of percus' sion, that is, cartridges developing a greater initial pressure and having a higher speed of ring are used.

This object is attained according to the present invention by this that there is arranged in the rearm a breech device characterised by a breech block forming a body having flat sides and tiltable around the longitudinal axis of the rearm and provided with locking lugs which engage in notches in the casing of the firearm. The breech block forms an appropriate quadri-lateral prism the base of which has a greater length than height and which is chamfered along a shorter length than the length of the body on the opposite parallel side-walls by parallel planes. Without counting that the arrangement according to the present invention considerably diminishes the height of the casing and thus also the weight of the firearm, a more advantageous formation of the breech block with. regard to a more favourable straining by the pressure of the gases produced in firing the cartridges, is obtained. Thus it is also possible to use cartridges with a greater powder charge and therefore also a more violent force of percussion.

The accompanying drawing shows the arrangement of the device according to the present invention in two modications. In Figs. 1 to 4 is shown the arrangement in the case of a hand operated firearm, which in Fig. 1 shows the longitudinal section of the breech block closed. Fig. 2 is a perspective View of the breech casing with the breech block open. Figs. 3 and 4 are transverse sections of the iirearm following the lines I-III and IV-IV of Fig. 1.

Another example of the arrangement of the breech device in an automatic gas operated firearm is perspectively shown in Fig. 5.

The irearm shown in Figs. 1 to 4 consists essentially of the barrel l, which is xed to the casing 2 of the breech by means of a screw thread; 3 is the front part of the stock, 4 is the upper part of the stock. In the under side of the casing 2 is arranged in a known manner the cartridge chamber 5 with the follower 6 charged with the spring l. The trigger mechanism 8 is of a known construction and sets the hammer 9 in action. On the rear part of the casing 2 is fixed the butt l0. In the casing 2 of the breech moves 65 theV breech block Il' with the striker l2 charged with a spring i2' and the ejector I3.

The breech block Il has the shape of a flat slab with its bottom and top faces chamfered or beveled at |l`y i4' outwardly from approximately the center longitudinal line of the face, the bevels being diagonally opposite, that is, the bevels of the top fa'ce being at the left of the center line and that of the bottom face at the right as seen in Fig. 2. The bevels extend from the rear end of the block forward a distance equal to the length of the arrow L in Fig.y 2. The angle of bevel is indicated by a which is preferably from 15 to 30. The forward end of the block is unbeveled and forms locking lugs i5, I5 adapted to be received in recesses Il, Il', respectively in the bottom and top wall of the case 2. The remaining portions of the top, bottom, and side wall of the casing form planes for guiding the` breech block in executing the movement by whichy the breech block passes into the closed or open position. Itwill be seen that the lugs I5, l5' have diagonal locking faces l'6, IS which engage rear end walls of the recesses Il, Il', respectively, when the block is tiltedr through the angle a into locked position. The lug l5* bears the bolt lever I8, which passes through a longitudinal slot in the casing 2 of the breech device, which ends in the locked posit-ion in a transverse slot 2B, enabling the transverse motion of the bolt lever when locking the breech block.

When firing the breech block is located in the position shown in Fig. 4, when the lugs l5, I5' engage in the recesses I1, Il' and the breech block rests on both walls I4, lli on the upper and under guiding Walls inside the casing. The back pressure of the propellant gases that acts at the moment of ring on the center of the breech block is taken up by the plane faces I6, I6. Assuming that the reaction pressure on the casing has the same effect as it would if all concentrated at the centers of gravity of the two diagonal planes, it will be seen from Fig. 4, that the reaction pressure in effect will be concentrated on two points, a distance apart and will be within the contour of the breech block body. This distribution of force or strain is much more favorable than in known breech block cylinders. The strain or distribution of force is much more favorable because the bearing length is shorter and therefore under the same conditions the breech block may be more charged respectively stronger and more explosive charges may be used.

After firing the rieman swings round the Ward movement of the breech block a new cartridge 2| is brought into the cartridge chamber and after having accomplished the locking movement the breech block is swung round at the locking angle a. As it is quite sufficient if the locking angle is about to 30, the movement of locking and unlocking requires much less time` than in the devices up to now in which it has been generally necessary to swing round the breech block by 90. This fact increases the speed of firing which in modern firearms is one of the most important requirements.

According to the invention the breech block may also be used in automatic rearms as may be seen in Fig. 5 in which is shown a perspective view and a fragmentary section of a gas operated firearm.

The firearm shown in the drawing .consists of the barrel I, the casing 2' for the breech, in which the breech block II, which isconstructed in quite the same manner as that in the preceding case, is movably located. The breech block is again chamfered at the two opposite edges Where the chamferings I4, I4 begin also at approximately a central longitudinal vertical plane through the prismatic body of the breech block. For actioning and governing there is a stud 22 fixed on the locking lug I5 which engages into the slot 23 at the end of the piston rod 24, whilst the piston 25 of the piston rod reaches into the gas cylinder 26 and is guided in a known manner in the casing 2 of the breech device. The gas cylinder is tightly fixed to the barrel by means of a sleeve 21. The forward movement of the breech device is assured by the buffer spring 28. The governing groove is chosen so that at the first shock of the gases on the piston the breech block remains still closed during a certain time and only when the piston 25 after having travelled through a certain distance leaves the gas chamber, it is when the projectile has left the barrel, through the effect of the curved part of the slot 23 a, swinging of the breech block II around the locking angle a takes place. After the unlocking has taken place, the piston rod 24 brings the breech block I I into the rear end position. For operating the breech by hand a handle 29 is formed on the piston rod.

The executions described are given only by way of example and Vmay be varied in details without departing from the scope of the invention especially as far as the governing of the breech Yblock and the like are concerned.

What I claim is: Y

1. In a breech block device, a casing, a breech block slidable in said casing and'guided'by walls thereof, said block having opposite flat sides each formed with a bevel extending along part of the length of the side and extending outwardly from a line located approximately centrally of its width, the unbeveled portions beyond the ends of the bevel forming locking lugs and said casing being formed with recesses adapted respectively to receive said lugs and means for turning said block from an unlocked position in which the unbeveled portions of said sides are in guiding contact with said Walls to a locked position in which said lugs are received in said recesses.

2. A breech block device according to claim 1 wherein, the block is in the form of a flat slab with top and bottom faces beveled and of greater area than the remainingV faces of the block and wherein the bevels extend forward from the rear endof the block and the lugs are located at the front end.

3. A breech block. device according to claim 1, wherein the block is in a form of a flat slab with top and bottom faces beveled and of greater area than the rear faces of the block, and wherein the bevels extend forwardly from the rear end of the block and the lugs are located at the front end, and wherein the lugs have flat rear faces and the recesses flat rear walls, and wherein, in locked position said faces and walls are in facial contact.

4.-A breech block device according to claim 1, wherein the face of the beveled portion makes an angle of 15 to 20 with the continuation of the unbeveled face.

JOSEF KOUCKY. 

